1. Field of the Invention
This invention relates in general to a power supply connection to a vehicle power distribution box and more particularly to a lever-operated cam device for securing a terminated power supply cable in electrical connection with a power distribution system.
2. Discussion of Related Art
An electrical junction block or power distribution box (PDB) is commonly used in automotive vehicles to streamline electrical system wiring by eliminating multi-branch wiring. The PDB consolidates relays, fuses, connectors, branch circuits and other electrical components in a single location. This is typically done by incorporating one or more bus bars or similar conductors into a housing. The bus bars are used to supply and distribute electrical power to the components for serving the vehicle electrical circuit requirements. The electrical power is usually provided to the bus bars through a power supply line from the vehicle alternator and/or battery. FIG. 1 illustrates how the electrical connection is typically made. The PDB 10 is broadly represented and has a protruding ledge 12. An electrically conductive bus bar 14 rests on the ledge 12 and extends into the PDB 10 for electrical connection with other bus bars in an internal power distribution system. A flat eyelet terminal 16 on the end of a power supply line 18 is fit over a threaded bolt 20 attached to and protruding from the PDB ledge. A nut 22 with an associated washer 24 is used to tighten the terminal 16 down on the PDB into electrical contact with the bus bar 14 and the electrical distribution system. This method requires separate nut and washer components and a wrench to turn the nut on the bolt. The method also presents problems such as stripping of the bolt threads with repeated service, and possible under-tightening of the nut leading to a poor electrical connection.
It is known in the art to use a hand-operated lever rather than a nut and bolt, and associated wrench, to secure battery terminals to posts on a battery. For example, U.S. Pat. No. 5,389,466 discloses a battery terminal for connecting an electrical wire to a battery post. The terminal includes an annular portion for fitting around and engaging the post. The annular portion has an open free end formed by initially spaced apart tightening plates. A lever connected to the terminal has an operating arm extending from a cam-shaped bearing portion with a curved first side and a straight second side. When the operating arm of the lever is pivoted toward the annular portion, the first side of the bearing portion pushes one of the tightening plates toward the other, pressing or squeezing the annular portion around the battery post. When the straight second side of the bearing portion comes into contact with the tightening plate, the lever is securely held in the position pressing the annular portion around the post. In this device, the lever and annular portion are essentially in the same plane, providing an adequate device for tightening a terminal around a post. But this does not suggest a workable device for pressing a flat power supply terminal into electrical contact with a bus bar in a power distribution box.
In Japanese Patent Application Document No. 10-144367, published May 29, 1998, a seat part is formed on a battery post. A terminal metal fitting is fit over the post and rests against the seat part. A washer-like spring member is placed over the terminal metal fitting. A lever having a cam part is pivotally mounted on a bracket. The bracket has a hooking piece for attaching the bracket to the seat part. The bracket is installed on the seat part with the cam part of the lever positioned over the spring member. When the lever is pivoted, the cam part pushes on the spring member and forces the terminal against the seat part. This device requires a specially formed battery post and seat part, and separate components such as the spring member. A need exists for a way to electrically connect a flat terminal on the end of a power supply line with a generally coplanar bus bar on a PDB without the use of tools, threaded or specially designed posts, and separable components.